Force compensating means for fluid translating device

ABSTRACT

A fluid translating device including a housing adjustably supporting a camblock which has a bore communicating with inlet and outlet ports formed in the housing. The bore has a rotor rotatably supported therein with the rotor having the vanes slidably supported in slots, the free ends of which engage the surface of the bore. The bore and rotor cooperate to define a sealing zone between the ports in a manner that the pressure of fluid is increased as it is transmitted between the ports. The fluid translating device incorporates force compensating means which counteract the forces developed by the pressured fluid on the camblock. The force compensating means includes plungers slidably supported in counterbores formed in the camblock and cooperating to define pressure cavities that are in communication with the sealing zone. Thus, pressured fluid is received from the sealing zone into the cavities and produces a counterbalancing force. Adjustable abutments extend from the housing and engage the free end of the plungers while the plunger is maintained in engagement with the abutments through springs located within the cavity.

United States Patent Jansson 1 Apr. 25, 1972 [54] FORCE COMPENSATING MEANS F Primary Examiner-Carlton R. Croyle FLUID TRANSLATING DEVICE Assistant EXD1mirllliOll"l1n J. \;lra llik & G d

' Attorne ress er, 0 smit ement or on [72] Inventorz. Birger Fredrik Jansson, Racine, Wis. y

[73] Assignee: J. 1. Case Company I [57] ABSTRACT [22] Filed. APR 13 1970 ,A fluid translating device including a housing adjustably supporting a camblock which has a bore communicating with [2i] Appl. No.: 27,866 inlet and outlet ports formed in the housing. The bore has a rotor rotatably supported therein with the rotor having the lidably supported in slots, the free ends of which en- 52 us. Cl ..41s/s1 vanes S gage the surface of the bore. The bore and rotor cooperate to 2 John/l6 f gg gq flgg. define a sealing zone between the ports in a manner that the 1 0 pressure of fluid is increased as it is transmitted between the [56] References Cited I The fluid translating device incorporates force compensating UNITED STATES PATENTS I means which counteract the forces developed by the pres- 719 634 2 1903 Austin .......Q.41s 31 Wed fluid The fme P 8 means 3 083 535 4/1963 Krafft et al 418/31 includes plungers slidably supported in counterbores formed |238870 9H9l7 Augustine 418/71 in the camblock and cooperating to define pressure cavities 2l5994l 5/1939 Guinness 418/31 that are in communication with the sealing zone. Thus, pres- 263l544 3/1953 Wilcox sured fluid is-received from the sealing zone into the cavities l449 12/1961 Ernst 7 and produces a counterbalancing force. Adjustable abutments extend from the housing and engage the free end of the plun- FORElGN PATENTS OR APPLICATIONS gers while the plunger is maintained in engagement with the i abutments through springs located within the cavity. 447,789 8/1927 Germany ..418/3l 2 Claims, 2 Drawing Figures an J0 I l 4;

w \b 58 f I a 2a 26 e2: 22 V23 /J8 .38-\ i 6 18 I 5922, 58 -16 16 J 56k s PATENTEDAPR 25 m2 3658, 146

34% 70 [722/6 7Z07 5 7967 Fflanssan FORCE COMPENSATING MEANS FOR FLUID TRANSLATING DEVICE BACKGROUND OF THE INVENTION pertains are very common in the prior art. One of the known types of fluid translating devices is what is commonly referred to as a reversible vane-type pump which includes a shaft supported for rotation within a housing with a rotor having vanes slidably supported in slots and keyed to the shaft. The rotor is received within a bore formed in a camblock or camring in a manner to produce sealing zones between inlet and outlet ports formed in the housing. Generally, the camblock is verti-' cally shiftable relative to the housing to vary the amount of fluid translated through the device, as well as reversing the direction of flow of the fluid between the ports;

As the fluid is transmitted from the inlet to the outlet port,

gagement with an adjustable abutment or stop defined on the housing. The plunger is normally maintained in contacting engagement with the abutment or stop by biasing means within the cavity and pressured fluid is diverted from the sealing zone into the cavity to produce a counterbalancing force on the camblock which is substantially in opposed relationship to the reaction forces on the internal surface of the camblock.

Furthermore, the present invention contemplates the formation of a plurality of individual force compensating means respectively in communication with different locations of each of the sealing zones so that the entire camblock is substantially balanced within the fluid translating housing. With such an arrangement, the deflections of the camblock normally encountered during the translation of fluid through the pump is substantially eliminated.

across the sealing zone, the pressure thereof is increased and 1 results in reaction forces being developed on the bore surface forming part of the sealing zone. While such reaction forces do not present any appreciable problems in small fluid translating devices, difficulties are encountered when the physical size of the devices is increased to increase the volume of the fluid transmitted from the inlet to the outlet port.

For example, with a large device of the type which has nine vanes supported in a rotor that is rotated at a rate of 2,000 R.P.M., each of the bore surfaces forming part of the respective sealing zones between the inlet and outlet ports will be rapidly subjected to the pressure of the fluid as each vane moves into the sealing zone area. Thus, as the vane enters each of the sealing zone areas, passing from the low pressure port to the high pressure port, the counteracting forces on the internal surface of the bore rapidly increase and then rapidly decrease as the vane leaves the sealing zonearea. Furthermore, as the same vane moves from the high pressure port to the low pressure port, the opposite surface of the bore forming part of the second sealing zone is rapidly pressurized'from the pressure of fluid in the outlet port. It will be appreciated that with a pump which is capable of operating at a rotation speed of 2,000 R.P.M., the reaction forces increase and decrease several thousand times during each minute of operation and it has been found that the fluctuation in counteracting reaction forces result in a vibration of the camblock within the pump housing.

. While mechanical locking of the camblock within the pump housing has been proposed, such mechanical locking renders it difficult for adjusting the output flow and the direction of flow through the pump. v

One type of such prior art balancing mechanism is disclosed in U.S. Pat. No. 3,465,682, issued to Phillip Hartmann.

BRIEF SUMMARY OF THE INVENTION The present invention contemplates incorporating a force compensating means within a fluid translating device of the type having a housing supporting a rotor for rotation about a fixed axis with a camblock cooperating with the housing and Furthermore, the particular force compensating means contemplated by the present invention readily allows for the movement of the camblock to different positions with an inexpensive mechanical device. Stated another way, by having the camblock substantially pressure balanced, the moving mechanism for varying the displacement as well as direction of flow of fluid through the reversible pump need not be capable of withstanding any substantial forces from the fluid being translated.

The illustrative embodiment of the present invention contemplates the formation of a first group of four fluid cavities in the upper end of the camblock with each of the fluid cavities being in communication at a different location with the upper sealing zone or lap space. Furthermore, the illustrative embodiment contemplates the formation of a second group of four such cavities in communication with different locations of the lower sealing zone or lap space of a reversible flow vane-type pump.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 shows a verticalsectional view of a fluid translating device having the present invention incorporated therein; and

FIG. 2 is an enlarged fragmentary sectional view taken generally along line 2-2 of FIG. 1.

DETAILED DESCRIPTION While'this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail one specific embodiment, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated.

FIG. 1 of the drawings discloses a fluid translating device 10 of the type commonly referred to as a reversible flow vanet ype pump. The fluid translating device 10 includes a housing 12 consisting of a central member 14 having a pair of side plates 16 secured thereto with the side plates each having a port 18.

' The fluid translating device further includes a shaft 20 supported for rotation within the housing 12 between the respective ports 18. As is common in pumps of this type, the shaft is supported by bearings (not shown) in opposite ends of the a means for counteracting reaction forces on the camblock resulting from the pressure of the fluid within the sealing zone.

More particularly, the present invention contemplatesdiverting some of the fluid from the sealing zone into cavities located in opposed relationship to the sealing zone to produce counterbalancing forces on the camblock at locations which are insubstantially opposed relation to the sealing zone.

The force compensating means of the present invention is inv the form of a cavity or recess defined in the camblock which slidably receives a plunger, the outer end of which is in enmember 14 and has a rotor 22 keyed thereto for rotation therewith. The rotor has a plurality of circumferentially spaced radially extending slots 24 each of which slidably supports a vane 26. The fluid translating device 10 further includes a camblock 30 which supports a camring 32 having an internal bore 34 which is in communication with the respective ports 18 through cutout portions 36 and openings 38. The respective cutout portions 36 terminate at a point spaced from a vertical plane extending through the axis of the shaft 20 so that the bore 34 in the camring 32 cooperates with the external surface of the rotor 22 to define sealing zones or lap spaces 40 and 42, respectively located above and below the rotor the respective ports 18.

In order to make the fluid translating device of the reversible type and of the type in which the output fluid is varied, the camblock 30 is supported for vertical movement between the ports 18 by suitable mechanism 44 so that the axis of the bore 34 may be disposed above or below the axis of the shaft 20. For example, if the axis of the bore is located above the axis of the shaft 20 and the shaft 20 is rotated in a clockwise direction, fluid will be transmitted from the left-hand port 18 through the upper sealing zone 40 and the pressure thereof will be increased or elevated as it is transmitted or translated to the right-hand port 18. Thus, the left-hand port will be in the inlet port while the right-hand port is then the outlet port. If the axis of the bore is disposed below the axis of the shaft 20, the fluid will be translated from the right-hand port to the lefthand port 18.

Assuming that the fluid received by the unit is translated from left to right and the pressure thereof is increased, as each of the plurality of vanes 26 enters the left-hand edge of the upper sealing zone 40, the pressure within the sealing zone between two adjacent vanes is rapidly increased thereby causing reaction forces on the internal surface of the bore 34 defined in the camblock 30. Likewise, as each of the vanes enters the lower lap space area 42, the internal surface of the bore will rapidly be subjected to the high pressure fluid in the outlet or right-hand port 18. Furthermore. as this vane then is moved across the lower sealing zone 42, and leaves the sealing zone, the pressure thereof will be rapidly reduced to substantially the inlet pressure to the pump.

As was indicated above, a large number of vanes and a substantial increase in pressure of the fluid between the inlet and outlet ports, as well as a high rotation rate of the rotor 22 within the bore 34, will cause a large number of increases and decreases in the reaction forces developed on the upper and lower internal area of the bore 34, which will result in undesirable vibration ofthe camblock in the housing.

The present invention contemplates equalizing the reaction forces developed on the camblock 30 by producing equal and opposite counteracting forces at points in substantially opposed relationship to the reaction forces discussed above. This is accomplished by utilizing fluid which is being translated by the pump and diverting this fluid at a point where the reaction forces are developed so that the counterbalancing forces will be substantially equal to the reaction forces.

More particularly, the present invention contemplates pressure compensating means located between the housing and the camblock which receive pressured fluid from the sealing zones to thereby produce counteracting forces on the camblock, which pressure balances the camblock within the housing 12. The pressure compensating means is in the form ofa plurality of pressure compensating units 50 with one group of units 50 cooperating with the upper sealing zone 40 while a second group of units cooperate with the lower sealing zone. It is contemplated that each of the groups of units will incorporate at least one unit, but the exemplary embodiment of the invention shows four such units cooperating with each of the zones 40 and 42. Since each of the force compensating units 50 is identical in construction, only one will be described in detail.

Each of the force compensating units 50 includes a counter bore or recess 52 extending from an adjacent surface of the camblock 30 with the inner end of the counterbore connected to the adjacent sealing zone through communication means 54. The communication means 54 includes a first opening 54a in the camring 32 and a second opening 54b in the camblock 3d. The counterbore or recess 52 slidably receives a plunger 56 to define a chamber or cavity 58 which is in communication with an area of the sealing zone 40. An O-ring seal 60 is interposed between the counterbore and the plunger 56 to prevent any fluid from being transmitted from the chamber The plunger 56 may extend directly from the adjacent portion of the housing member 14, but it is preferable that the plunger be formed in two parts with a first element 62 threadedly received in an opening 64 and a second element 66 slidably received in the counterbore or recess 52. With this arrangement, the adjustable element 62 defines adjustable abutment or stop means for the other element or plunger 66 and the adjustable stop means 62 may be positioned to compensate for the vertical adjustment of the camblock 30 within the housing 12. Also, the adjustable stop means or element 62 may be utilized to vary the size of the chamber or cavity 58.

In order to assure that the element 66 is at all times in contacting engagement with the stop means 62, each of the force compensating units includes biasing means in the form of a spring 70 having one end received in a further counterbore 72 defined in the element 66 with the opposite end of the spring 70 engaging the base of the counterbore 52. The compression spring 70 will at all times maintain the adjacent ends of the first and second elements 62 and 66 in contacting engagement with each other.

An inspection of FIG. 1 will show that each of the cavities or chambers 58 is in communication with a different area of the adjacent sealing zone 40 or 42.

The operation of the device is believed to be apparent from the above description. Considering first the operation of the upper group of force compensating units 50, as each vane 26 moves into the sealing zone area 40, the fluid trapped between adjacent vanes begins to become pressurized because the volume between respective vanes is being decreased. The pressured fluid is transmitted through the communication means or apertures 54a and 54b and is received within the lefthand chambers 58. Thus, the pressured fluid received in the cavity or chamber 58 will produce an equal and opposing force within the base of the cavity 52 and will counteract the forces developed on the internal surface of the camblock 30 and more specifically the internal surface of the camring 32 defining the bore 34.

Continued movement of the subject vane will eventually cause the vane to move past the left-hand apertures'54a and thereby allow the pressure of the fluid within the left-hand chambers or cavities 58 to slowly be reduced to substantially the inlet pressure of the fluid translating device. However, when this condition appears, the right-hand apertures 54a will still be in communication with the sealing zone and thus will produce the counteracting forces in the bases of the righthand recesses or counterbores 52. The same condition will occur along the lower sealing zone except in the lower sealing zone 42 the procedure will be substantially reversed. Thus, as each vane passes the right-hand lower apertures 54a, the righthand chambers 58 will be subjected to the higher or outlet port pressure and this higher pressure will subsequently be decreased as the next adjacent vane passes the right-hand edge of the lower sealing zone. Furthermore, the left-hand aperture 54a will first be subjected to the higher pressure of the trapped fluid between two adjacent vanes and will subsequently be allowed to drop to substantially the pressure of the inlet port as each vane passes the left-hand edge of the lower sealing zone 42.

It will be appreciated that the present invention provides a simple and efficient manner for at all times maintaining a balanced condition of the camblock or camring within the pump housing. Furthermore, the amount of counteracting forces on the outer surface of the camblock is directly dependent upon'the pressure of the fluid which develops the reaction forces on the inner surface of the camblock. With such an arrangement, the vibration of the camblock is virtually eliminated and the mechanism for producing the counteracting forces can readily be adjusted to allow for movement of the camblock within the housing.

What is claimed is: 1

1. In combination with a reversible fluid translating device including a housing having inlet and outlet ports on opposite ends thereof; a rotor supported for rotation in said housing between said ports, said rotor having circumferentially spaced radial slots respectively supporting vanes; and a camblock supported for vertical movement between said ports, said camblock having a bore surrounding said rotor and said bore having cutout portions at opposite sides thereof communicating with said ports, said rotor and bore cooperating to define first and second sealing zones between said cutout portions and located above and below said rotor; and force compensating means between said housing and said camblock, said force compensating means including means defining first and second groups of counterbores in said camblock, said groups of counterbores respectively disposed adjacent said sealing zones above and below said rotor; communication means between the respective counterbores and circumferentially spaced portions of the adjacent sealing zones; a plunger in each of said counterbores and cooperating therewith to define a cavity; a plurality of adjustable stops supported by said housing and respectively disposed in the path of one of said plungers; and biasing means in each of said cavities, s'aid. biasing means maintaining the respective plungers in engagement with an associated stop whereby fluid translated across said sealing zones will be received in the respective cavities to produce counteracting forces on said camblock for reaction forces produced on said camblock by fluid in said sealing zones.

2. The combination of claim 10 in which the first and second groups of counterbores in said camblock above and below said rotor include a counterbore adjacent each end of a sealing zone, and wherein the communication means between the respective counterbores and the circumferentially spaced portions of the adjacent sealing zones are defined in part by inclined passages each communicating at one end with said bore and communicating at the other end with one of said counterbores. I 

1. In combination with a reversible fluid translating device including a housing having inlet and outlet ports on opposite ends thereof; a rotor supported for rotation in said housing between said ports, said rotor having circumferentially spaced radial slots respectively supporting vanes; and a camblock supported for vertical movement between said ports, said camblock having a bore surrounding said rotor and said bore having cutout portions at opposite sides thereof communicating with said ports, said rotor and bore cooperating to define first and second sealing zones between said cutout portions and located above and below said rotor; and force compensating means between said housing and said camblock, said force compensating means including means defining first and second groups of counterbores in said camblock, said groups of counterbores respectively disposed adjacent said sealing zones above and below said rotor; communication means between the respective counterbores and circumferentially spaced portions of the adjacent sealing zones; a plunger in each of said counterbores and cooperating therewith to define a cavity; a plurality of adjustable stops supported by said housing and respectively disposed in the path of one of said plungers; and biasing means in each of said cavities, said biasing means maintaining the respective plungers in engagement with an associated stop whereby fluid translated across said sealing zones will be received in the respective cavities to produce counteracting forces on said camblock for reaction forces produced on said camblock by fluid in said sealing zones.
 2. The combination of claim 10 in which the first and second groups of counterbores in said camblock above and below said rotor include a counterbore adjacent each end of a sealing zone, and wherein the communication means between the respective counterbores and the circumferentially spaced portions of the adjacent sealing zones are defined in part by inclined passages each communicating at one end with said bore and communicating at the other end with one of said counterbores. 